钙和水杨酸对亚适温弱光下黄瓜幼苗光合酶活性和基因表达的影响

为了探明钙和水杨酸对亚适温弱光下黄瓜幼苗光合作用的调控机理,以‘津优3号’黄瓜为试材,用10 mmol·L-1氯化钙(Ca Cl2)和1 mmol·L-1水杨酸(SA)喷施预处理幼苗,每天喷1次,连续3 d,之后置于光照培养箱内进行亚适温弱光处理(18℃/12℃,PFD 100μmol·m-2·s-1)。结果表明:亚适温弱光可使黄瓜幼苗生长量大幅度下降,光合速率(Pn)以及核酮糖–1,5–二磷酸羧化/加氧酶(Rubisco)、果糖–1,6–二磷酸酯酶(FBPase)、甘油醛–3–磷酸脱氢酶(GAPDH)、果糖1,6–二磷酸醛缩酶(FBA)、转酮醇酶(TK)的活性与其m RNA表达明显降低,但Ca Cl2和SA预处理的黄瓜幼苗的降低幅度明显较小,可见钙和水杨酸可以通过提高光合酶的活性及其基因表达,缓解亚适温弱光对黄瓜幼苗光合作用的影响,增强其对亚适温弱光的适应性。

Foliar Spray Calcium and Salicylic Acid Improve the Activities and Gene Expression of Photosynthetic Enzymes in Cucumber Seedlings Under Low Light Intensity and Suboptimal Temperature

The purpose of this paper is to investigate the regulating mechanism of calcium chloride （CaCl2）and salicylic acid（SA）on the photosynthesis of cucumber（Cucumis sativa L.）seedlings under suboptimal temperature and low light intensity.‘Jinyou 3’cucumber seedlings were used as the experimental materials. Seedlings were pre-treated with either distilled water，10 mmol ? L-1 calcium chloride（CaCl2）and 1 mmol ? L-1 salicylic acid（SA）for 3 d. Afterwards，the pre-treated and non-pretreated（control）seedlings were displaced into growth chambers and treated under suboptimal temperature （day/night temperature is 18 ℃/12 ℃）and low light intensity（100 μmol ? m-2 ? s-1）. The results showed that suboptimal temperature and low light intensity decreased the growth，photosynthetic rate（Pn），theactivities and mRNA expressions of ribulose 1,5-biphosphate carboxylase/oxygenase（Rubisco），fructose-1,6-bisphosphatase（FBPase），glyceraldehyde-3-phospha -ate dehydrogenase（GAPDH），fructose-1,6-bisphosphate aldolase（FBA）and transketolase（TK）significantly. 10 mmol ? L-1 CaCl2 and 1 mmol ? L-1 SA led to an increase in the growth volume，Pn，activities and mRNA expressions of Rubisco，FBPase，GAPDH，FBA and TK. The results suggest that CaCl2 and SA have beneficial effects on the adaptation to low light and suboptimal temperature in cucumber seedlings. It speculates that this adaptation might be related to the observed increase in the gene expression and activity of the Calvin cycle enzymes.